The present invention relates to an apparatus for coupling elevator car doors with shaft doors.
Elevator door coupling devices with movable cam parallelograms at the car door, which engage in a roller pair at the shaft door and entrain the shaft door in the case of previous unlocking, are generally known.
Further, devices are known with rollers which are spread by rotation of a roller lever at the car door and straight arms at the shaft door in which the rollers engage.
The Swiss patent specification No. 365 844 shows a respective rotatable roller double lever at each of a shaft door and a car door, which lever stands in operative connection with the corresponding counter means at the opposite door. During opening, the roller double lever is rotated indirectly by the door drive by way of the counter means for the purpose of unlocking and, after the unlocking, the entrainment of the opposite door takes place, but certainly not free of play, because only one roller rests in the entraining element.
The U.S. Pat. No. 2,432,293 shows a shaft door entrainer at the car door with a rotatable roller double lever, which in the coupled state embraces a vertical entraining straight arm at the shaft door and entrains this free of play. The roller double lever is actuated or rotated by an auxiliary drive, which is derived from the door drive, by way of a cam disc.
The door coupling shown in the U.S. Pat. No. 5,105,916 similarly employs a rotatable roller double lever, wherein during opening this is rotated by an actuating lever until a straight arm at the shaft door is engaged around and the shaft door is entrained.
A rotating door coupling is shown in the U.S. Pat. No. 5,485,896. In this case, in the region of the door zone, a roller double lever is rotated by an actuator until both rollers lie against the inner walls of a sheet metal channel arranged at the shaft door and entrain the shaft door.
All solutions known hitherto can be realized only with a relatively large threshold gap between the car and the floor. The threshold gap must necessarily be as large as the engagement depth of the entraining means plus a tolerance distance of at least 5 millimeters. That results in threshold gaps of, for example, 20 to 25 millimeters. Such threshold gaps are an obstacle for roller trolleys with small wheels and moreover can involve an accident risk through catching of shoe heels. Furthermore, smaller objects can fall down into the elevator shaft.